The Death of Sleep
by Kathstiel
Summary: Castiel has broken the wall between Sam and his memories of the Cage. Instead of saving Sam by taking the hallucinations into himself, Cas works to find another way to save his friend. Sam/Castiel
1. Chapter 1

**NOTE:** Castiel has broken the wall between Sam and his memories of the Cage, released the Leviathans, and promptly gone missing with no idea of who/what he really is. Dean finds Cas, who regains his memories, and they rush to save Sam who is being driven mad by his hallucinations of Lucifer. Instead of saving Sam by taking the hallucinations into himself, Cas works to find another way to save his friend, and in the process finds out more about himself and Sam's time in the Cage than he ever wanted to know.

 **IMPORTANT:** Stretches the M rating to breaking point. Mentions of rape, torture and suicide. I've tried to tone it down as much as possible, but if you're worried, please don't read!

 **Chapter 1:**

"He's in real trouble, Cas. It's so fucking bad. I don't know how much longer he can hold on," Dean glanced at the angel slumped in the passenger seat of the Impala, but not for more than a second because his foot was pressing the accelerator as far to the floor as it would go.

"Cas?" Dean asked sharply when the angel didn't immediately reply. Cas had been mostly silent since he'd regained his memories, probably wallowing in guilt for murdering half of Heaven, unleashing the Leviathans on the world and, oh yeah, _destroying his brother's mind!_

"You don't need to worry Dean. I will do everything in my power to restore your brother," Cas said softly, still staring out the window.

"Damn right you will," Dean muttered into the steering wheel. He felt Cas shrink down a bit more in his seat, but couldn't bring himself to care. He hoped Cas felt guilty. Damn guilty. He hoped the angel wallowed in his guilt until he drowned in it, as long as it didn't interfere with healing his brother. He glanced down at the speedo for the thousandth time, willing his baby to go as fast as she could. When he'd left Sam at the motel to find the 'faith healer' who had turned out to be Cas things had been, well, grim. His fingers flexed around the steering wheel.  
 _Just hold on a bit longer Sammy, just a little bit longer_.

* * *

Castiel sat in the passenger seat of the Impala as Dean explained for the thousandth time about Sam and what he needed the angel to do, as if worried Cas would refuse to help or would disappear without warning. He couldn't blame Dean, after what he'd put them all through it was a wonder the hunter hadn't killed him on the spot. Cas knew he would do whatever the brothers asked, it didn't matter what it was. If Dean or Sam needed him to walk through the fires of Hell itself he would do so, he owed them that much and more.

Cas felt for his angelic powers and sensed his wings rustle in response. Another failure, he hadn't regained his memory until Dean had pulled up at a gas station, and by that point they were so close to the motel it would have been pointless to fly them there. He slumped further against the window, the cool glass a soothing contrast to the turmoil in his mind. He'd had a lot to process since Dean had found him, but none of that mattered just now because Sam needed him. Needed him because Castiel had destroyed him, had broken the wall between Sam and the memories of his century in the Cage.

Castiel shuddered, sick with shame, and pulled his coat a little tighter around him. He'd been both touched and saddened that Dean had kept it, aware that he didn't deserve the love and concern that such an action signified.

Sam hadn't answered his phone since before Dean found Cas, so by the time they pulled up at the motel Dean was a nervous wreck and Cas wasn't much better. Without a word they got out and Dean hurried to the door, hesitating for just a moment before slotting the key in the lock. Cas trailed behind, he could tell that Dean was scared of what he would find on the other side of the door, which said more than words ever could about the deterioration of Sam's condition. Cas steeled himself as Dean took a deep breath, pushed the door open and walked inside.

* * *

Sam looked up from where he was sitting on the edge of the bed, a smile of greeting plastered on a face that was shockingly gaunt, and so pale that the only color belonged to his bloodshot, red-rimmed eyes. His hair was lank and greasy and tremors ran up and down his body like little electrical shocks. Even though Dean had prepared him Cas was still shocked at the pitiful sight the youngest Winchester made. He hesitantly moved into the room, unsure of his welcome.

When Sam saw Cas his eyes widened with shock, and terror ghosted across his face, so quickly that the angel wasn't sure he'd seen it at all.

"Hello Sam," Cas said awkwardly, then added unnecessarily, "It's me."

Sam's reaction to those four simple words was complete and utter disbelief.

"No." he said simply, and turned away.

Cas felt the rejection like a blow.

"Sam…" he started, walking further into the room. "I'm so sorry Sam. So very, very sorry." He was shocked to see a tear slide slowly down Sam's cheek at those words, as the broken man began to shake like he would shatter into a thousand pieces. "Oh Sam, what have I done to you?"

Dean reached out to Sam but he flinched back so violently it was as if the hunter had hurled a high voltage wire at his brother instead of offering comfort. Dean drew his hand back like it had been burned and shoved his hands in his pockets for good measure.

"It's ok Sam, we're going to help," Cas said as gently as possible.

Sam shook his head mutely and pushed the heels of his hands into his eyes.

"Sam, look at me," Cas coaxed, crouching down by the bed but not moving to touch the terrified hunter. "We're going to figure this out. I know this is all my fault, but I'm going to fix it. Dean and I are going to help you, I promise."

It seemed the more the angel talked the more terrified Sam got. Dean glared at Cas to shut him up but it was too late; Sam let out a broken sound and shrank back like a wild animal. Everyone froze, until after a heartbeat of tense silence Sam's face relaxed and broke into a horrible parody of a grin.

"Oh very good, very good!" Sam snickered, clapping his hands together. Dean and Cas looked at each other in bemusement and no small amount of alarm.

"Clever. You really had me going that time. 9 out of 10," Sam waggled a mocking figure at Cas, who stared at it like it was a venomous snake. "Worse than the time I thought I found the way out, not as bad as when fake 'Cas' came to rescue me."

"Sam…?" Cas asked, a terrible suspicion beginning to dawn.

"Sammy?" Dean said at the exact same moment. The hunter and the angel exchanged another worried look.

"Oh come on!" Sam mocked. "The game's over. You've been caught. Now let's get back to the _physical_ torture please. I'm sure this time shredding the skin from my body will make you feel better about being locked in here. Where are we up to? I lost count around the ten thousand mark."

Cas felt every word of this speech like a physical blow; he looked over at Dean and could see his horror and revulsion mirrored in the hunter's chalk-white face.

Sam's eyes darkened as he watched them. "Come on. Get to it already." Another long heartbeat of silence ensued and the hunter huffed impatiently. "Well, if that's how you're going to be I guess I'll have to start the party all by myself."

With that declaration Sam was suddenly up and moving. Cas and Dean were still frozen in place, Sam's move had been too unexpected and the shock of his earlier accusations hadn't yet worn off. Consequently Cas was almost too slow to react when the distressed hunter decided to break the tableau in as decisive a way as possible. Spinning around, Sam grabbed a lamp and flung it into the full-length mirror behind the door, causing it to shatter in an explosion of silver glass. Quickly the hunter ripped out a broken shard and, heedless of the blood dripping from his lacerated hand, raised it up with the clear intention of plunging the jagged splinter into his jugular.

It took a long moment where the world seemed to turn in slow motion for Cas to shake off his shock and leap into action. The angel reacted with the speed of thought, using every ounce of his inhuman reflexes to blast the shard out of Sam's hand, leap forward and slap a palm to his forehead, putting the hunter deep into unconsciousness. As Sam slumped into his arms, Cas turned to face Dean, who was still in the process of leaping forward and had to pull up short to prevent knocking both his brother and the angel to the ground. They locked eyes above Sam's head, which was now cradled to Cas's shoulder, and shared a moment of pure confusion, disbelief, and horror.

Dean helped the angel lay his brother down as comfortably as possible on the hard motel bed, despite Cas's protest that he didn't need help. Cas supposed Dean needed the physical contact to reassure himself that his brother was ok. The angel was startled by this thought, when had he become so attuned to human behavior?

Cas shook himself out of that unhelpful line of thought; Dean had finished pulling off Sam's shoes and was clearly waiting for Cas to finish healing his brother's hand. Cas noted that Dean's own hands were shaking violently, and there were tears standing at the corners of his eyes. He gently laid Sam's now-healed hand back on the mattress and turned to face his friend.

"I wondered how he still recognized me after over a hundred years locked away," Dean said unsteadily, staring at his brother's limp form. "I mean, who remembers someone after a century of torture? I had a hard enough time after less than half that."

Cas nodded grimly. "It's because he saw 'you' all the time. Even for my family that's… monstrous."

Dean scrubbed his hands on his pants as if trying to wipe away the memory of what just happened. He took a deep breath.

"Can you heal him?"

Cas looked at Dean gravely. "This isn't a physical ailment. I can try to put the wall back up, but it might not be possible. I'm sorry Dean. I'll do all I can."

Dean drew in a shaky breath and nodded. "I know it's cowardly of me Cas, but I need to get out. Go for a drive or something. After what we just learned I'd say he's definitely a flight risk, but I don't want to tie him down. Can you watch him for me, please?"

Cas nodded again. "Of course Dean. I will watch over him."

Dean shook himself out of his frozen state and turned to go, before looking back at the angel.

"Don't let me down, Cas. Not again."

Castiel stared at the floor after his friend had gone, another wave of guilt washing over him at Dean's parting words. He knew he deserved more than just words for what he had done to the Winchesters; after all, what Sam was going through right now was completely his fault. His arrogance and hubris had led him to practically destroy the two people in the world he cared for above all others, and Cas knew he could never expect forgiveness from them. Not that he would ever forgive himself.

A small noise came from the bed and the angel turned to look sharply at his sleeping charge. No human should have been able to fight the unnatural sleep Cas had put Sam into, but it looked like that's exactly what the hunter was doing. Cas could see his eyes roving around under his eyelids, and his lips trembling as if he was trying to open his mouth to scream.

It soon became clear that Sam was going to wake up and Cas didn't want his presence to scare the hunter into another attempt to take his own life. The angel made the snap decision to remove himself from Sam's perception and only reveal his presence if Sam tried to run. Cas didn't look too closely at his more selfish reason for going 'invisible'; he couldn't bear to see that look of pure horror and hatred on his friend's face again.

* * *

Once he was sure he was alone Sam's eyes popped open. He knew rationally that Lucifer was watching him, but he couldn't see him right that second and that was a blessed relief, one not often afforded in the Cage. He also knew it made no sense to run, after all he was trapped not only in the cage but also in his own mind, but he couldn't shake the instinct. Fight or flight still applied, even in Hell.

Sam sat up and ran his fingers through his hair. He'd been so certain this time that it was real. Obviously Lucifer had spent the first hundred years of his imprisonment just warming up. After all, what's a century in the scheme of eternity?

Just as he thought that happy thought Lucifer showed up on Dean's bed.

"Where have you been?" Sam snapped, not at all happy to see the monster but needing to know why he hadn't shown up immediately, like he usually did. Any change in routine was suspicious, and to be treated with caution.

"Here, Sammy. I'm always here for you, you know that," his tormentor said in a sickening parody of concern and love. Sam just grunted. Standing invisibly behind the bed Cas watched his friend converse with thin air and narrowed his eyes.

"Are you happy I figured it out, or did I spoil some big plan of yours?" Sam asked casually, pulling his boots on. Lucifer grinned lazily.

"I knew you'd figure it out eventually," he shrugged. "Did it cause you pain?"

"Of course," Sam said matter-of-factly, stuffing clothes into his bag to give himself something to do with his hands except strangle the smug bastard sitting on his brother's bed. That course of action never ended well.

"Then I am satisfied," Lucifer stated, smiling again as he settled back on the bed. "Out of curiosity, what gave me away?"

"Castiel," Sam said. The angel jerked backwards at hearing his name, thinking somehow Sam could see him. When he realized Sam was just talking about him to his hallucination he relaxed a little. Until Sam finished his sentence.

"He was too concerned, you know? I know Cas has never really done more than tolerate me. Boy with the demon blood and all that."

Castiel felt sure his heart had shattered into a million pieces, despite the physical impossibility of such an action. The guilt and grief he felt at those words caused him to sway on his feet and he nearly revealed himself, nearly showed himself to Sam to tell him he was wrong, so very wrong. But he stopped himself, because this conversation was too important to miss, it gave too much insight into the direction the hallucinations were pushing his friend.

"Why is it still going?" Sam asked finally, stopping on his way to the door to ask his tormentor the question that had been hanging between them. He didn't _want_ to know the answer, but he _needed_ to know.

"Oh my dear, stupid boy," Lucifer smirked, "because it isn't over yet, of course." With that he snapped his fingers and was gone. Sam stared at the place he had been for a long moment, then turned towards the door and walked right into Castiel.

* * *

Sam looked at the angel in confusion for just a second, before leaping backwards with all the strength he could muster.

"Oh _no_ ," he whispered brokenly, scrabbling even further away. He knew what this was. The blue eyes of the angel bored into him as he tilted his head to the side in that achingly familiar gesture.

"Sam…" the gravelly voice said as Cas reached tentatively towards him. Sam shrank back until he was in the corner, trying in vain to make his large frame into a smaller target. The angel moved another step forward and Sam began to babble, words pouring out of him in a hopeless attempt to distract Lucifer and put off the inevitable.

"I wondered when you were going to pull out this card," he sneered with a bitter laugh, staring straight at 'Castiel'. He saw the angel's brow furrow in confusion; Lucifer was really going all out on the realism this time. But of course he was, that was the only way he could make this work and truly break Sam, really destroy the last shreds of sanity he still hopelessly clung to.

"You know, it was bad enough when you raped me wearing my brother's form," Sam continued, as calm as if he was talking about the weather, or some other ordinary, mundane thing. "Of course, it didn't work as well as you hoped, I knew it wasn't him. On no plane, in no reality, no matter the provocation would the real Dean do that to me. But Cas, who the fuck knows what Cas is really capable of?"

Sam was looking straight into the angel's eyes as he said this and saw him shudder beneath the weight of those words. A smidgen of doubt about the falseness of this reality treacherously planted itself in his mind, but he squashed it ruthlessly. Of course this wasn't real, if he let himself think that again it would unravel his mind even quicker, bring Lucifer his satisfaction even sooner. And every second Sam could defy that monster's wishes was a moment he would take, with glee.

"Sam…" Cas begged, hands curled in his trench coat, real distress evident in his tone. Sam stared back with all the hatred and loathing he could muster. How dare Lucifer take this form, how _dare_ he defile Cas's memory in such a way?! As the angel stood there, indecisive, the hunter gave in to his fear and shut his eyes. For the first time in over a hundred years, Sam prayed.

" _Cas, I know you can't hear me because you're dead. And I'm in the Cage. But I wanted to say goodbye. There's no coming back from what's about to happen. But I know it's not you doing this to me. And if it was, so be it. I would give anything to you. Be anything for you. I love you, Castiel. I will always love you. Goodbye, my Angel_."

* * *

Castiel didn't know what to do. Sam had worked himself into a state and wasn't allowing the angel anywhere near him. He kept his hands curled in his clothes in order to reduce the threat Sam felt, but every time he moved forwards the hunter's face twisted with such pain Cas thought his heart would break anew. And then Sam revealed what had happened to him, how Lucifer had worn Dean's form and done something appalling, something unspeakable, unforgivable. Cas felt himself fill with a rage so white-hot he thought he might burst into flames.

And then, and _then_ , Sam _prayed_ to him. Sam still had faith in him, after all the pain he had inflicted, after all the damage he had done. Sam still believed. In _him_. Not only that, Sam loved him. Sam, who had given his very soul to protect the world, _loved him!_ At this revelation Castiel felt his Grace, already roused by his earlier rage, burst to life within him.

As Sam finished his prayer he scrambled up, determined to take whatever came next on his feet, not cowering like a child. As he opened his mouth to get out one last scathing remark, he noticed the angel's expression. The look on Cas's face was nothing Sam could put a name to, it was completely inhuman, something ancient and beautiful and terrible that was usually hidden below the surface. Sam felt his face go slack in shock, and then suddenly the angel was all white, glowing so brightly it hurt to look at him. Through the brightness Sam could see only Cas's piercing blue eyes, and the shadow of an enormous pair of wings that encompassed the entire room. He breathed in deeply, feeling the angel's grace reach out to him, and oh, he knew the feel of that grace. There was only one being in the world it belonged to, and it certainly wasn't Lucifer.

" _Castiel!_ " he whispered, falling to his knees.

* * *

The angel let the light inside him die out as he looked down at the awestruck hunter, who was still on his knees, gazing at him with an expression that contained so much wonder that if Cas had needed to breathe it would have taken his breath away.

"It's really me, Sam," he said, holding out a hand to help the youngest Winchester to his feet. Instead of getting up, Sam clutched Cas's proffered hand and pulled him to his knees, grabbing the angel's face in his hands and staring at him with an expression that Castiel couldn't name, but that made him want to cry. He knelt there passively as Sam ran his fingers over his face, through his hair, fisted his hands in his trench coat. Eventually the hunter seemed satisfied and pulled Castiel to him in a rough hug.

"Thank you," he murmured into the angel's ear, tears evident in the thickness of his voice. Cas put his arms around the hunter and gingerly hugged him back, trying to comfort without confining.

Sam released Cas and sat back, staring at him again until suddenly a shadow crossed his face and he let out a dismayed groan. Cas immediately sprang to his feet, on high alert, his angel blade appearing in his hand without conscious thought. When the angel found no obvious danger he looked down at his charge inquiringly.

Sam looked back up at him with abject misery.

"I'm sorry, Cas," he whispered. Cas looked at him in confusion. What could _Sam_ possibly have to be sorry for? If this was a human movie, Cas would certainly have been cast as the bad guy in this scenario.

Sam shifted uncomfortably. "Those things I said, I wasn't in my right mind, ok? I never wanted you to know… what happened. I never wanted that. Please… please don't tell Dean."

Cas felt his throat close and tears well up in his eyes for the third or fourth time that day. He reflected bitterly that life had been so much simpler when he'd been a 'proper' angel. He mutely held out his hand again and this time Sam did use it to help himself up. He was so weak it took him a few tries to get to his feet. Cas felt an irrational stab of anger.

"You listen to me, Sam Winchester," he ground out. "I won't tell your brother, but you are never to apologize to me again. For anything. This is my fault, not yours. If you were to take an angel blade and cut out my heart, I would not expect an apology. It would be no more than I deserve."

"Oh, Cas," Sam breathed out, and Cas knew the hunter was about to make excuses for him, was about to try and make him feel less guilty. The angel couldn't deal with that right now, couldn't deal with anything approaching forgiveness, so he held up a hand to stop the flow of words. Sam wisely fell silent.

"Now," Cas said sternly, "lie down. You might not sleep but the evening's events have put too great a strain on your heart. You need to rest."

Sam nodded obediently and lay down, his eyes never leaving the angel's face, as if afraid he might disappear. Cas sat on a chair beside the bed, determined to stay by his friend's side and watch over him, for the rest of his life if necessary.


	2. Chapter 2

**Warning:** Scenes involving torture. Sorry Sam!

 **Chapter 2:**

Two days later, two days of Sam having conversations with the air and screaming in his 'sleep', a state of semi-doze that was all the broken man seemed able to achieve, Cas was starting to understand what was happening to Sam. And starting to think that maybe, just maybe, there might be something he could do to help.

He was jolted out of his thoughts by Dean clicking his phone shut, remembering that the hunter had been following up a lead on the leviathans.

"The information is good, I have to go check this out." Dean shifted uncomfortably, Cas knew he wanted to stay with Sam, but they both knew Dean's constant hovering was beginning to wear on his brother.

"You should go," Cas said abruptly, "I will watch Sam." Sam glared at that, he hated being 'watched'.

Still Dean hesitated. "Is there nothing…" he trailed off, looking at Cas, pleading in his eyes. Cas hesitated.

"I could try one thing, but it will not be easy. It also has a high probability of failure."

"Of course," Dean said sarcastically. "It just wouldn't be our lives if something could be done the easy way." Sam just sat and stared at the floor, not really paying attention. He had run out of hope a long time ago. Cas looked at his despondent friend and sighed.

"Sam needs to be able to fight off Lucifer. By which I mean he needs to have a weapon, and the faith that that weapon will work, that it will be there to protect him." Cas took a deep breath, knowing how presumptuous his next statement was after everything he had done to the brothers. "I can be that weapon, if Sam will let me. I can walk in his dreams, fight for him, fight with him, until he feels safe, until he can bring up my memory as a barrier against Lucifer's memory."

Dean started to scoff, how could the angel protect Sam when he'd done this to him in the first place? But Sam held up a hand, and Dean fell silent.

Sam looked straight at Cas, and the angel could see the hunter weighing up the implications.

"What you'll see in my mind, it will be hard for you. Are you sure you want to do this?"

Castiel stared back at the youngest Winchester, who was putting Cas's well-being above his own. _Again_. In that moment the admiration the angel felt for this broken human being almost overwhelmed him and he nodded, unable to speak. Sam huffed out a laugh.

"Don't look at me like that Cas, I'm not the angel in the room. Keeping you out of my mind isn't entirely selfless, your ex-angel brother, who _really_ needs anger-management classes, did a lot of things I'd prefer to keep to myself."

Cas nodded again. He knew what Sam was referring to, but it didn't change what needed to be done.

"Right then. Well, no time like the present," Sam sighed, lying back on the bed. "Let's get this over with before I change my mind. You'll have to knock me out, Cas. Use an iron bar if you have to."

"Hitting you with an iron bar would defeat the trust-building purpose of this exercise," Cas said, deadpan. The tiny smile that lifted the corners of Sam's mouth was worth the feeble attempt at humor, and caused Cas's heart to lurch strangely in his chest.

Dean rolled his eyes dramatically and stomped off to have a shower.

* * *

Dean came out of the bathroom and arched an eyebrow at the sight of Cas holding his sleeping brother's hand.

"Hand-holding part of the cure?" he asked nonchalantly as he grabbed his hunting gear from beside the bed.

"Physical contact is unnecessary. However he wouldn't let me leave, and it seemed to calm him when I held his hand."

"I bet it did," Dean said, with a sly look. Castiel realized then that Dean knew of Sam's feelings for him, had probably always known, and felt relieved that he had enough control over his vessel to stop the blush that threatened to stain his cheeks.

"Bet that's not the only thing Sammy wants you to hold," Dean added, seeing the invisible line and dancing right across it anyway.

"Dean!" Cas spluttered, ruthlessly clamping down on the urge to remove his hand from Sam's and place it around Dean's neck instead.

"Alright, alright!" Dean held his hands up in surrender, before suddenly turning serious. "Just, don't hurt my little brother, ok Cas?"

"Of course," the angel replied, confused. Was he holding Sam's hand too tightly? He looked down to check, and Dean sighed.

"Emotionally, Cas. I meant don't break his heart."

Ah. Cas understood now. He nodded solemnly.

"Any more than you already have, I mean," Dean added, a little of the anger he had internalized for the sake of his brother bleeding through in that statement. Cas stiffened, locking eyes with Dean, who stared coldly back until Cas dropped his gaze and nodded again.

"Good," Dean muttered before leaving, fully focused now on the mission ahead.

* * *

Castiel had no need for sleep so he was able to spend a long time wallowing in guilt. He spent an equally long time looking at the hand that he held, feeling the dry, feverish warmth of the palm, and the way Sam's fingers held his tightly, even in sleep. He couldn't say why but the feeling of Sam's hand in his comforted him, and he felt a surge of fond protectiveness towards the battle-scarred human who held his hand so trustingly.

Cas was paying such close attention to his charge that he was immediately aware of the change in Sam's breathing; again he was pulling out of unconsciousness and into a dreaming state far too quickly for a human. Castiel could only assume it was Lucifer's influence, determined not to allow his captive any rest. The angel looked down at the broken man, waiting to see if it was just a momentary discomfort or if the nightmare was upon him. When Sam drew in a deep breath to scream Cas knew the time had come to try and repair some of the damage he, in his arrogance and stupidity, had inflicted. Although he didn't need to breathe he drew in a deep breath of his own and entered Sam's dreams.

Immediately Cas was overwhelmed by the smell of the place he found himself in. The sizzling meat stench was only the surface of the miasma, underneath that the smell of fear and hate and rage was almost overpowering. The next thing he noticed was the sounds; above the crackling of the fire that seemed to be almost everywhere he could hear a distant screaming, and a soft whimpering in the corner. When he turned to look for the source of that sound he immediately doubled over to vomit. It didn't matter that he was an angel and didn't have anything in his stomach to heave up, or that this was a dream and not real. It wasn't just a dream, it was a memory, and the look of Sam's body in that memory was more than Cas could take in and still remain upright.

Ruthlessly he got himself under control and reached out a shuddering hand to the barely-human thing in the corner, unable to find a spot on Sam that wasn't skinless and bloody. He touched his friend as gently as he could, wincing at the feeling of raw flesh underneath his fingers, and healed him.

When he looked up Sam was whole again, but completely unresponsive. He stared at Cas without seeing him, stared right through him, at something behind him. The angel stiffened and whirled around.

"Well, well, well," Lucifer greeted him, flashing a smile that that seemed oddly white, until Cas realized his teeth were the only part of him not covered in Sam's blood. Cas drew in a deep breath. This was it. He had to become Sam's protector, not just in the real world, but in his head too. It might take time, but if Cas could save Sam from his nightmares he might be able to break the cycle, and give the hunter a weapon to use against the hallucinations. But it would only work if Sam trusted him, totally and completely. One failure to protect and it would all be over. Cas steeled his resolve.

"You're repugnant," he informed his fallen brother coldly. "Sam is coming with me. You will no longer touch him."

"Repugnant?" Lucifer's eyes gleamed with mirth. "Big words little brother. Big words from someone who slaughtered so many innocent people, so many members of our _family_. You know what's important to Sammy, Castiel? Family."

Cas sighed. This was not a good start. Sam had begun to take notice of the conversation, his eyes darting from Cas to Lucifer and back again. Castiel itched to drive his angel blade into his fallen brother, to carve every last second of Sam's suffering into his flesh. But he stilled his hands. This was not a fight that would be won in battle; this was a fight for Sam's heart and mind. For his soul.

It was a battle Castiel intended to win. At any cost.

"I know. I also know how you used Sam's love of his family, his love for his _brother_ , as a part of your sick little game."

Ah, a palpable hit. Cas could see Sam start to bristle at Lucifer, start to think that maybe Cas was there as savior, not tormentor. Lucifer could see it too. He sneered.

"And where have you been, Castiel? You know who has been with Sammy all this time? I have. Not you. You know he screamed out your name, called to you constantly the first few years he was down here," Lucifer grinned wickedly as Castiel flinched. "Only the first few though. He gave up soon enough. Knew he couldn't count on you to be there. Not like he can count on me. Right, Sammy?" Lucifer glanced at Sam, who looked down, defeat etched across his features.

Castiel knew then he was losing this battle, that Lucifer's influence was too ingrained on Sam's subconscious to allow him even a shred of hope in this place. The angel knew he had to do something that would really get through to Sam, and soon.

After a second of indecision he looked down into the face of the man who had placed all his trust, all his faith in a broken angel and suddenly knew what to do. He locked his gaze on Sam's as he sank down to his knees next to him. The angel's heart broke just a little bit more as Sam flinched away from the hand he gently placed on his cheek. Without thinking too closely, acting purely on instinct now, Castiel brought his other hand up to cradle Sam's terrified face, and leaned in to kiss him.

* * *

Sam woke up, but instead of being bathed in sweat, shaking and gasping, he had a strange sense of well-being. The last fragments of the dream slipped from his mind as he stretched, feeling better than he had in ages. Until he looked up and saw Cas staring at him with such intensity he thought the angel's eyes would burn a hole right through him. He froze like a frightened rabbit. When the angel didn't do anything more than stare Sam swung his legs gingerly over the side of the bed and sat up, running a hand through his disheveled hair.

"Cas?" Sam asked softly. "Everything ok?"

Cas was silent a moment longer, before looking away in a slightly guilty gesture that made Sam's stomach clench.

" _Cas_?" he asked warningly, heart rate speeding up. Cas huffed out a sigh and looked back again.

"Do you remember your dream?" he asked eventually.

Sam frowned. "No, what… _oh_. Did you try it?" He stretched his limbs experimentally, grinning when he noticed they didn't shake as much as before. "It must have worked, I feel marginally less like complete and total shit." He looked around hurriedly. Lucifer was absent, but that didn't mean anything. It would hurt Sam more to see him after convincing himself he was on the way to fixing this mess, so that would be when he would appear.

"I did try, but I'm not sure it was very successful. I suspect it will take some time," Cas said, looking away from Sam, then back again with that same weird intensity, then away again. Sam was confused, until a horrible thought suddenly occurred to him.

Oh _hell_. Cas hadn't walked in to a dream about him had he? Sam had a pretty vivid imagination when it came to the angel; it would explain why Cas was acting so strangely. He felt his neck start to heat up and practically jumped from the bed.

"Well, I guess we'll see," Sam said hurriedly, grabbing his toothbrush to give himself an excuse to put a door between himself and the angel. He felt Cas's eyes boring holes in his back all the way to the bathroom. Once inside he pressed his back to the door and blew out a breath, trying desperately to remember the dream. What had happened? Had he ruined everything?

* * *

Cas watched Sam hurry to the bathroom with more haste than required and wondered if he'd ruined everything. Again. He glared at the door that separated him from the youngest Winchester and didn't know whether to be relieved or disappointed that Sam didn't remember the dream. Cas ran a finger over his lips absently, trying and failing not to replay the last moments of the dream. His plan had seemed to work, but he couldn't shake the feeling that he'd done something wrong.

He was so lost in thought he nearly jumped out of his vessel when the door slammed open and Dean stumbled in, a hand clutched to his blood-soaked stomach. Sam was out of the bathroom and at his brother's side before Cas had even managed to stand.

"Cas! Help!" Sam cried urgently, as he gently maneuvered his brother onto the bed. Dean groaned, there was so much blood Cas couldn't immediately pinpoint the source of the bleeding. When he removed Dean's shirt with the help of his angelic powers, both Sam and Cas hissed in a collective breath. Dean's abdomen was a mess, it was clear that he'd not only been shot but stabbed, and more than once. Cas realized immediately that Dean had barely minutes left, it was a miracle he'd made it as far as the motel.

"Dean!" Sam practically shouted, holding his brother's hand in a death grip. "I'm here Dean, Cas is here. It's going to be ok. You hold on. You just hold on, you hear me?!"

Dean grunted something which might have been a reply but Cas knew was the first sign that his soul was about to flee his body. He could feel the reaper hovering nearby, all too ready to do its job and rid the world of one of the pesky Winchester boys.

"Not today," Cas growled at it. Sam started but Cas didn't have time to explain. Quickly he pushed Sam out of the way and laid his hands on Dean's most grievous wounds, healing them as fast as he could. He shuddered; the damage was so severe it was taking all of his considerable strength to hold back the encroaching darkness of Death. He could feel Dean's organs begin to give out and poured all of his healing, all of his unspoken apologies, all of his love for the brothers into the broken body beneath him.

What seemed like hours, but was only seconds later Dean gasped and began to cough, hacking up great gouts of blood. Sam held his brother's head to the side so he wouldn't choke and looked at Cas, the question obvious in his eyes. Cas nodded mutely, too drained to speak. Dean would be ok. Sam turned back to his brother and Cas sat back, staring at his blood-covered hands. They seemed symbolic, somehow.

* * *

Dean slept for several hours while Cas and Sam kept a silent vigil, both too shocked and exhausted to speak. When Dean finally woke and told them how it had been a trap, that he'd been ambushed, Cas was angry, as angry as he'd ever been.

"Why didn't you call me?" he asked so calmly that only the brothers, who had known him long enough to see a little behind the angel mask, would have been able to see the anger and hurt in his eyes.

Dean snorted. "They didn't exactly give me time to ask for my one phone call."

Cas hissed out a breath. "That's not what I meant. I know I've hurt you Dean, but you must know by now that when you pray to me in a time of need I will appear."

Dean and Sam both looked so shocked that Cas felt a momentary stab of confusion through the anger.

"You can hear our prayers again, Cas?" Dean asked slowly.

Cas nodded, confused. "Of course, why would I not be able to?"

Cas had a sudden thought, if the Winchesters thought he didn't have his 'listening ears' on, then… oh. He chanced a look at Sam and saw the exact moment he realized Cas had heard his goodbye prayer a few days previously. Saw the blood drain from the hunter's face as he kept his gaze locked firmly on his brother, avoiding the angel's eyes with fierce determination.

Dean was looking as angry as Cas had felt a few moments ago.

"If you have enough mojo to answer prayers, where were you after you got out of the river? Sam and I prayed to you for days, Cas. _Days_. We begged you to come back. Are you telling me you heard that and _didn't do a damn thing_?"

Cas huffed out an exasperated breath. "I didn't have any memories! I thought you were a symptom of my healing gift, the voices of the needy crying out to me!"

"Well we _were_ the fucking needy, Cas! You released those big-mouthed assholes from purgatory, broke Sam's _sanity_ , and left us for dead! I'd sure as hell class that as _needy_!"

Cas felt trapped. He rustled his wings in agitation, something the Winchesters wouldn't notice but which reminded him that he could leave at any moment.

Sam glanced at him sharply, and Cas wondered if he'd made a movement or a sound that indicated his desire to run.

"I…" he began, but Sam cut him off.

"Dean, Cas just saved your life," he pointed out reasonably. Cas relaxed a bit, until Sam turned towards him, his expression unreadable. "Cas, sometimes you can be a real dick, you know that?"

Dean grunted agreement and the angel bristled, knowing instinctively that this was about walking in Sam's dreams knowing the way Sam felt, not about any of the other things that had come before. That was too much for Cas, who was now such a mess of _human_ emotions, anger, hurt, shame, guilt, and some other ones he had no name for, that he had to get out. Had to go and try to be an _angel_ for a while, had to try and regain some of the emotionless calm that had been his life before he met these fragile, infuriating, _intoxicating_ humans.

Sam opened his mouth to either yell some more or apologize, he wasn't sure which, but it was too late. The angel was gone.

* * *

It had been a few days since Cas had left the motel room in a flutter of wings. Both brothers had refused to call him back, but for very different reasons. Dean because he was stubborn, and could hang on to a grudge for a long time. Sam because, well, he wasn't sure he could ever face the angel again knowing that Cas knew all about his treacherous, immoral thoughts. Sam knew how wrong it was for him to love something as pure as Castiel; he was an abomination, filled with demon blood and a vessel for the damned _devil himself_ and Cas was, well, a literal Angel. But he couldn't help it. From the first time he had looked into those infinitely blue eyes he had been lost. The one consolation had been that the angel was unaware of his feelings.

And now Cas knew. Had known before he'd gone into Sam's head. Had therefore known exactly what buttons to push to get Dream Sam on side. Given that information the hunter had a pretty good idea why Cas had looked so guilty. Had a pretty good idea what Cas might have said or done to break Lucifer's hold over him.

It made him furious. Furious with himself because he'd put the angel in that position, furious with his dream self who had probably said or done something really stupid to cause _that look_ in Castiel's eyes. Furious with the angel for using a part of him so secret and private, even to help him. But mostly furious _because he couldn't remember!_

He scrubbed his hands over his face, still mortified beyond belief. The only up side to the whole sorry affair was that he hadn't seen Lucifer since Cas had walked in his dream.

"That's because you've been doing a fine job of torturing yourself without me around to help," said a smooth, horribly familiar voice from the chair beside the bed. Sam jumped half out of his skin, giving a little yelp of alarm.

Dean whirled around. When he saw his brother staring at the empty chair like it contained a ravening lion his face fell.

"Sammy?" he asked softly, padding over to the bed. When Sam didn't respond he clicked his fingers in front of his brother's eyes, causing him to jerk back and blink rapidly, before focusing on Dean's face.

"He's back, isn't he?" Dean asked, already knowing the answer. Sam nodded, resignation and a tinge of hopelessness evident in his eyes and the slump of his shoulders.

"Well really," Lucifer said, examining his fingernails, "I never left. You think your pet angel could scare me away? No. I _own_ you, Sammy." The fire that flashed through Lucifer's eyes at those words promised a banquet of unending suffering, and Sam shuddered.

"We need to call Cas," Dean said firmly, "he said it could take time to work properly, but he can't do anything if he isn't here."

"Cas, Cas, Cas, Cas," Lucifer mocked. "I am so _sick_ of hearing that name. First you scream it at me until I'm forced to tear out your tongue, then you scream it at me with your mind, and then, indignity of indignities, your precious _Cas_ rips you from my clutches before I'm done playing with you." He sighed dramatically, casually tossing a ball of fire from hand to hand. "Fine, bring him here. I'll burn off his wings. I'll toast him until his eyeballs melt. He took my vessel from me, so I'll char his to the bone. It's only fair."

Sam gritted his teeth and turned away from his tormentor. Something stuck in his mind though. Something had changed. Never before had Lucifer admitted that he'd been rescued. And then something else occurred to Sam that made him hunch his shoulders with shame. Despite everything else he had done, Cas _had_ attempted to rescue him from Hell, admittedly returning without his soul, but even his angel didn't have the kind of mojo that required. And in return he'd insulted his friend and hurt him so much he'd fled without saying a word to defend himself. The hunter wondered briefly if the weight of this guilt was yet another aspect of Hell.

Sam's face filled with misery, and Lucifer smiled.

* * *

Another day passed. Sam had made Dean promise not to bother Castiel, but the fact was there would soon be no other option. Dean had his suspicions about why Sam didn't want the angel poking around in his head anymore, but he wasn't about to let unrequited love be the reason Sam died. That was way too much like living in a chick flick. Besides, considering the way the angel had been looking at his brother before he left, Dean wasn't so sure the love was completely unrequited any more. Whether the angel knew it or not remained to be seen and was, frankly, beside the point.

It wasn't long however before the decision was taken out of his hands. One minute they'd been sitting there, eating lunch, well, Dean had been eating lunch and Sam had been moping and poking at his pile of lettuce, the next Sam was on the ground, writhing in agony.

Dean was by his side in moments, holding his brother as he screamed and cried for what seemed an eternity. Just as he was sure that Sam's lungs couldn't possibly take the strain any more his brother cried out one name - _Castiel!_ \- before falling silently, ominously still.

* * *

Castiel was sitting on a park bench by a lake when it happened. He'd been sitting in that same spot ever since he'd fled from the Winchester's words. He supposed that made him a coward, but he couldn't bring himself to care. He'd tried to push the emotions away, but he'd been on Earth too long, been in a human vessel too long. It was no longer possible to be indifferent to the humans, he felt too much. But at the same time he hadn't been on Earth long enough, he didn't understand even half of what he was feeling. His emotions were a jumble, sometimes he was sad, sometimes guilty, sometimes all he could think about was the look in Sam's eyes as they kissed, the feel of their lips pressed together. It made Castiel uncomfortable, as if he had lost control of his vessel.

One minute he was sitting there, thinking these dire thoughts, the next he heard Sam's voice cry out his name, full of terror and agony. Before the last syllable had finished rolling around in his head he was gone, the only sign of his passing a few leaves swirling as though caught in a whirlwind.


	3. Chapter 3

No warnings this time, except for plenty of angst. Sorry Cas!

 **Chapter 3**

Dean nearly had a heart attack when Cas materialized next to him. Before he could say a word the angel had leant down and placed a palm on his brother's chest.

"How long has he been like this?" the angel asked intently, pinning Dean with his glacial stare.

"The hallucinations started a day ago," Dean said, staring down at his brother. "He only just collapsed though. Cas, what's happened? Can you fix it?"

"You should have called me sooner," Cas said harshly, his hand still on Sam's chest, feeling the reassuring, if too fast, beat of his heart.

"I would have but…" Dean trailed off, looking uncomfortable.

 _But Sam didn't want me here;_ Cas finished the thought, filing away the stab of hurt to examine later. Right now he had bigger problems to worry about.

Cas lifted the youngest Winchester as if he weighed no more than a feather and laid him gently on the motel bed. That mission completed he shucked off his boots and coat, loosening his tie as he stretched out beside his unconscious friend. He arranged himself so his hand was resting on Sam's chest, with the rest of his body fitted beside the hunter, touching without restricting movement.

"Uh, Cas?" Dean asked, rubbing the back of his neck in an unconscious gesture of embarrassment.

"What, Dean?" Cas gritted out, annoyed at the interruption. Sam might not have long to live, he didn't have time to answer stupid questions.

"Why are you… you know what, don't tell me," Dean grumbled, sitting in the chair by the bed. Cas stared at him levelly.

"Most of my consciousness will be in Sam's mind, but enough will be left in my vessel to heal Sam, to keep him alive while I search for him." He waited until Dean nodded sharply, his jaw clenching at the unspoken implication that his brother would not survive without help.

"We might be unconscious quite some time," Cas added, after he was sure Dean had nothing further to say. "Sam's gone so deep into his mind it will be hard to find him. If we do not awaken after an hour, pray to me. I will hear and return."

He didn't wait for Dean's nod this time, instead closing his eyes and reaching out for Sam's thoughts. It was a process he had performed many times in order to speak to Dean and Sam in their sleep; this time was worryingly different, the youngest Winchester's essence eluded him for a long time before he finally caught enough of a trace to follow.

* * *

Usually when Cas appeared in a mortal's dreamscape he simply stepped into whatever world their subconscious mind had created, seeing it as they saw it. He was therefore fully prepared for another episode like the last, when he had walked into Sam's memories of the Cage. What he wasn't prepared for was to feel like he'd stepped into the eye of a tornado. He staggered backwards as his coat flapped around him, completely overwhelmed by the swirl of memories sucking him down into the vortex.

As he fell he felt himself buffeted on all sides by swirling images, glimpses of days driving with the brothers in the Impala, sitting with them at human diners, fighting monsters side-by-side, and other shared moments of friendship or danger. When the swirling finally stopped it took Cas a long moment to find his bearings. What he saw made his stomach clench.

The angel found himself standing outside his body, the first day he had met Sam. He saw the disdain in his eyes as the boy with the demon blood had reached out to shake his hand; and Sam's crestfallen expression when he had hesitated before returning that simple human gesture of respect. He cringed inwardly at the hurt and confusion in the youngest Winchester's eyes. He suddenly longed to go back to that moment, grasp that hand in his and tell the young hunter ' _everything will be ok. I will watch over you_.'

Before he had time to understand the significance of the first memory, the landscape changed again. This time he found himself in the town the brothers had rescued from Famine's clutches. He watched himself say that everyone hungered for something, sex, attention, drugs, love… and saw Sam's guilty look for the first time. Sam had hungered for the demon blood; but by the way he looked at Castiel in that memory, that wasn't all he had hungered for. He watched as Sam and Dean shared a fond grin as he shoveled burgers into his vessel's mouth as fast as he could. That wasn't the most dignified memory for the angel, but seeing the brothers smile like that, with real affection, warmed something deep inside him.

Another shift. Now Cas saw Sam after his soul had been returned, relived the moment when Sam refused to hug him. But he saw it differently now, instead of seeing it as a rejection, he saw it as Sam saw it. He felt Sam's unwillingness to place his Hell-stained, human paws on the celestial being he adored. And deeper than that, a fear hidden behind the Wall, well below the level of conscious thought. The fear that Castiel was just another manifestation of Lucifer, the fear that if he touched him, the angel would disappear.

Cas cursed himself, the signs of Sam's eventual breakdown had been clear even then, how had he not seen it? He was supposed to be an Angel, supposed to protect the humans in his charge. How had he managed to fail this one human so spectacularly?

A flash, and Castiel was surrounded by a ring of fire. He closed his eyes in shame. He knew this memory well, had brooded on it often in the last few days. Sam, Dean and Bobby, confronting him about spying on them. He saw again the disappointment on the brother's faces when he admitted to working with Crowley. Watched as he asked Sam to trust him, told him that he was still his friend, and saw the way Sam had looked at him, like his heart was broken. He saw anew how he'd tried so desperately to make Sam look at him the way he used to, by admitting that he had been the one to raise Sam from the Cage. And then Sam's suspicion, ' _Wait… did you bring me back soulless… on purpose?!_ '

Next was a memory he wished he could wipe from existence; him, standing in that room, bursting at the seams with power, his friends cowering in fear and dismay. He saw, again for the first time, Sam's expression of horror as he plunged the angel blade into his back, moments after he had said 'I have no family.' And realized suddenly that Sam hadn't just been trying to save Dean and Bobby, but had been trying to save him too.

Sam's essence faded and he barely caught the thread in time. This time when he recovered enough to look around he realized he was looking in on last dream he and Sam had shared, just before he had leaned in to kiss his terrified friend.

By any measure of what the angel understood about human kissing it hadn't been a passionate kiss, unsurprising considering Sam had just been tortured and his tormentor was standing over them. But it had been tender, and had conveyed more of Sam's feelings for him than words ever could. After initial resistance Sam had melted into him, had raised a tentative hand to tangle his fingers in Cas's hair, nudging him closer. The little helpless moan Sam had given as Cas shuffled nearer had caused goose bumps to rise all over his supposedly angelic vessel. Disturbed by his reaction he had terminated the dream, but not before noting the dissolution of the Cage around them.

Cas watched it all happen again, and found himself wishing he hadn't ended the dream so abruptly.

He realized then that the visions hadn't been random; they'd been a linear description of pivotal moments in their history, a set of psychological breadcrumbs Sam had left during his descent into madness.

* * *

When Cas followed these breadcrumbs to their source, he wasn't sure what he'd find. Sam trapped in the Cage? Sam in the void of unconsciousness? When he finally did spring free from the swirl of memories he found himself instead beside a field, shrouded in semi-darkness, illuminated by a sky filled with millions upon millions of stars. The Impala was parked by the side of the road, and Cas looked around quickly, searching for his friend. He finally found Sam lying on a blanket, staring up at the night sky. He didn't acknowledge Castiel as the angel approached, other than to shift a little to the side, a tacit invitation for the angel to lie down.

Cas did lie down, and stared at the sky along with his friend. They stayed like that for several minutes, until he couldn't bear the silence any longer.

"Sam…" he began, hesitantly.

"Cas," Sam replied, warning in his tone.

Cas fell silent, but propped himself up on an elbow to study his friend. Sam's face was serene; the worry lines that usually resided between his brows wiped clean. He looked younger, at peace. But he didn't meet Cas's eyes, preferring to stare up into the night sky.

Castiel felt an urge unlike any he'd ever felt, he wanted to reach out and smooth Sam's hair away from his face, wanted to turn Sam's head so the hunter would look into his eyes, wanted to feel Sam reach up and run his fingers through his vessel's hair like he had in the dream.

"Sam," he said again, more firmly this time. Sam finally turned his head to meet his eyes, and there was look of acceptance in them that caused Cas's stomach to drop.

"You will die if you stay here," he said harshly, too frightened by that look to sugar-coat the truth.

"I know," Sam replied, a small smile curving his lips, "I think that's the best outcome, don't you? Things can't continue the way they are and… I'm a disaster, Cas. I hurt everyone, destroy everything I touch."

Cas vehemently disagreed. The thought of losing Sam made him feel like he would be sick at any moment. His heart clenched painfully in his chest and his body broke out in a cold sweat. He reflected grimly that he clearly didn't have as much control over his vessel in Sam's dreamscape as he did in the real world.

"That's not true, Sam," he said forcefully, "Dean needs you. I… I need you."

Sam narrowed his eyes. "I know what you're trying to do Cas, and it won't work this time."

Cas tried a change of tactics. "Where are we, Sam?"

Sam smiled, starlight shining in his eyes as he looked back up at the heavens.

"In a field not far from Bobby's house. I used to come here occasionally to look at the stars. Sometimes I'd imagine one of them was you, looking down on me," Sam blushed, but it was a fleeting embarrassment. Sam Winchester had no use for embarrassment in these, the final moments of his life.

Cas's heart lurched in his chest, first from happiness, then from guilt.

"I saw many memories of the two of us as I came here," he confessed, looking away from Sam and out across the field.

"Oh?" Sam asked casually, but Cas could see the sudden tension in the hunter's shoulders.

"I… I feel like I've failed you, Sam," Cas admitted, "Some of the memories of the two of us were happy, but mostly they involved me hurting you in some way."

Sam hummed noncommittally. "I suppose it could be seen that way, taken out of context," he said. "But, Cas, you only ever had good intentions. It was never malicious intent behind your actions."

"You know where the road paved with good intentions leads," Cas said bitterly, not sure why he was pushing the issue so much. It wasn't forgiveness he was after, he certainly didn't deserve that. So what was it? Punishment? Acknowledgement? The angel wasn't sure.

Cas's eyes treacherously found their way back to Sam's. The hunter was looking up at him with something close to amusement, a very different reaction than the one Cas had expected.

"Stop focusing on the things that have gone wrong, Cas. Remember, I'm the one who chugged liters of _demon blood_ and started the damn _apocalypse_. It doesn't get more fucked up than that." Sam shifted up onto his elbows, finally seeming to take an interest in the conversation, letting go of the terrifying indifference that had so frightened Cas.

"Do you know what I see when I look at you?" he asked gently. Cas shook his head mutely, he wasn't sure he wanted to know.

"I see everything that is good and pure, everything that is righteous and honorable, compassionate and worthy. And not just because you're an Angel, we've met plenty of angels who were complete assholes. I can name ten off the top of my head, Uriel being number one. But because you are you. You are Castiel, and to me, you are perfect."

Cas's heart filled with so much emotion, he hardly knew what to do, where to look. The hand he wasn't using as a prop for his head flopped about uselessly in a few aborted attempts to reach out to his friend. Finally he remembered the kiss from the Cage, and leaned over, pressing his lips determinedly against Sam's. Sam didn't pull away, but neither did he respond, other than a brief sigh after Cas withdrew.

Cas was confused. "Isn't this what you want?" he asked, plaintively. Sam sighed again and sat up, finally turning to face Cas fully for the first time since this strange encounter had started. He reached out to take one of the angel's hands in his own.

"Yes," he said with a sad smile, "it's all I've ever wanted." He held up his other hand as Cas started to speak. "But not like this. I don't want this, if you're only doing it to save me and not because..." he trailed off, but Cas understood.

"That's what I did wrong then," the angel said regretfully, looking down at their interlocked hands. "You were angry because you thought I did something I didn't want to do, in order to save you."

Sam's hand tightened around the angel's. "Yes," he said, "although I'm sorry for what I said afterwards, I know you were just trying to help. And I am grateful for that help."

Cas took a deep breath, a strange habit he'd picked up from being around so many humans, and looked into Sam's eyes. "But I did want to do it," he said, realizing suddenly that it was true.

Sam's expression didn't change, apart from a softening around the eyes. "Cas…" he started.

Cas didn't wait for him to finish, enough words had been said. Instead he reached out and pushed Sam back on to the blanket. Sam fell with a surprised grunt, Cas was stronger than the hunter, even here in the deepest corners of his mind. Cas followed Sam's fall until he was on top of him, pinning him down. He couldn't help a slight inward smile at the utterly shocked expression of the man below him. Sometimes he thought the brothers forgot that he wasn't just an angel, but also a warrior, a veteran of many battles.

Slowly, finding his way like the novice he was, Cas leaned down and pressed his lips against Sam's, a soft, feather-light kiss. He didn't know the right words to use, so he tried to convey everything he was feeling with the gentle touch of his lips. The soft noise of longing Sam made against his mouth caused all the hairs on Cas's vessel stand on end.

No, he corrected internally, not vessel. Here he was just Castiel, manifested in Sam's mind the way Sam saw him, at one with the body he inhabited.

He shivered as Sam's arms snaked around his back, feeling the strength in those arms as they pulled him closer. When Sam began to kiss him back properly Cas was stunned by power of his own response. The hand that wasn't holding him up seemed to move of its own volition as he caressed Sam's face with his thumb and tangled his fingers in his hair. He was on fire; the touch of Sam's lips on his was both too much and not enough.

Cas suddenly understood humans in a way he never had before, understood why they persisted in touching and rubbing up against each other all the time, even when it served no discernible purpose. He wondered how they stood it, feeling even a fraction of this jumble of emotions and physical sensations all the time would be _maddening_.

He never wanted it to end.

* * *

Sam had decided he was quite content to die; after everything they'd been through a peaceful death, here in this favorite place, was more than he could ever have reasonably expected.

But then Castiel came to find him, as he always did. He was selfishly glad Cas would be with him at the end, and although he'd only half expected him to show, it certainly wasn't a shock when he did appear. What _was_ a shock was the way the angel was now on top of him, his lips pressed urgently to Sam's, kissing him with the same keen-edged desperation Sam himself felt.

All Sam's self-sacrificing 'good of the many' thoughts flew out of his head as his mind went completely blank, utterly empty of everything except the angel in his arms. He gently rolled them so Castiel was on his back looking up at him, his hair deliciously disheveled, clothes askew, blue eyes staring into him with that soul-piercing intensity.

Sam caught his breath; he'd never been more turned on by anything in his life. With incredible difficulty he stopped himself from giving in to the urge to simply tear Cas's clothes off; he realized he had to take this slowly. Cas might have lived for millennia uncounted, but it was his first time experiencing this kind of physical interaction.

As Cas reached for him he wondered how long those noble sentiments would last before he shredded the angel's clothes with his damn _teeth_.

He leaned down and placed his mouth over Castiel's, bringing his more experienced touch to the encounter. He gently teased at the angel's lower lip until he opened his mouth for him and deepened the kiss, using his lips and tongue and the fingers curled in Cas's hair to say everything that was in his heart. Cas's hands roved up and down his back, eventually clutching at his shoulder blades, trying to bring him closer.

Sam's hand moved lower without conscious thought, rucking up Cas's shirt so he could trail his fingers across bare skin.

" _Sam_ ," Cas breathed, his breath hitching as the hunter lowered his head to kiss the angel's neck, teeth gently grazing the sensitive skin.

As Sam's hand splayed over Cas's waist a couple of fingers slipped below the waistline of his pants to rest over his hip bone. At that simple touch the angel let out an almost sinful moan of longing; a sound that went straight through Sam like a jolt of electricity. He pulled back, breathing heavily, suddenly aware that if he didn't stop soon things were going to get seriously out of hand.

Cas looked up at him with a slight look of betrayal; his hair was a complete mess, his lips were swollen from kissing and his pupils were blown so wide there was hardly any sign of the heart-stopping blue that Sam had fallen so hard for.

He was utterly gorgeous.

"Oh _Cas_!" Sam groaned, running his fingers through his hair. No one, not even a celestial being, had any right to be so fucking _sexy_.

Cas opened his mouth to say something, but then cocked his head to the side, as if listening. Sam felt the body beneath him tense, and shot the angel a questioning look.

"Dean," Cas said by way of explanation, "I told him to call to me if I hadn't come back after an hour." He tilted his head again, and Sam bit his lip hard enough to draw blood, the sharp pain the only thing stopping him from reaching down and continuing to kiss his angel senseless.

In his position straddling the angel's hips he could feel quite obviously how Cas was responding to him, and wondered idly if Cas's vessel would be as responsive back in the physical world. He shifted his hips mischievously, trying to get the angel to pay attention to him, whatever his brother had to say it could damn well wait. Especially since he didn't want to think about his brother right now.

As Sam moved against him Cas's mouth dropped open in a startled gasp and his eyes glazed over, a hint of red flushing his cheeks as his hands desperately grasped at the hunter's thighs. Which was exactly the reaction Sam had been aiming for.

The hunter smirked, thinking extremely blasphemous thoughts about the angel underneath him. He was just about to give in and act on some more of those thoughts, good intentions be damned, when Cas held up a hand, his eyes darkening.

"What's wrong?" he asked, as Cas started to grumble under his breath.

"Your brother is not only calling me, he is using a number of profanities and blasphemies to do so," Cas said, his face scrunching up into the expression Sam and Dean secretly liked to call 'grumpy Cas.'

"Way to kill the mood, big brother," Sam groaned, reaching out a hand to smooth away the worry lines that had appeared on Cas's brow. The angel leaned into the touch with a sigh.

"We have to go back," Cas said reluctantly. "Your physical body won't last much longer with you locked so deep inside."

"And my mind?" Sam asked softly. "I felt the madness sucking me down, my sanity… it flew apart." He shuddered, remembering the moment he had finally broken under the strain of Lucifer's attention.

"This seems to be a safe place," Cas replied thoughtfully. "It's protecting you. But it won't last much longer either." He pointed past Sam towards the sky, where a jagged crack had appeared among the canopy of stars.

Sam tensed and rolled off the angel, lying back down on the blanket. He held Cas's hand, idly stoking his thumb across the angel's fingers. Cas snuggled in close, his head against Sam's shoulder.

"Will this be different, out there?" Sam finally got up the courage to ask.

Cas didn't answer. Sam thinking about the outside had been all the leverage the angel needed to pull them both back to the surface of consciousness.

* * *

Cas groggily raised his head, realizing immediately that he was almost fully on top of Sam, not beside him the way he had been when he'd launched himself into the hunter's subconscious. When he heard Sam laugh he followed his gaze to where Dean was sitting, his eyes screwed shut and his fingers shoved in his ears. Cas almost blushed; obviously some of what was happening inside Sam's mind had manifested itself in the physical world. He could still hear Dean ranting at him in his mind.

 _'Cas, you get your feathery ass back here and stop molesting my little brother! Or did you forget that he's_ dying _? Castiel?! You hear me, you son of a bitch?!'_

Cas sighed and crawled off the bed, shaking Dean's shoulder. The hunter yelped and nearly fell off the chair, glaring up the angel before quickly checking on his brother. Sam gave him a weak thumbs up and he relaxed.

* * *

"So…" Dean said, avoiding his brother's eyes. What had been seen could not be unseen, or rather, what had been heard could not be un-heard. "Now that you guys are…" he gestured vaguely between his brother and the angel, unable to think of a label that wouldn't end up with Sam's fist in his face, or Cas blasting him into his constituent atoms. He swallowed and tried again. "Is Sam… cured?"

"Despite what the media would have you believe, love does not conquer all," Cas said, still seeming vaguely ruffled, almost like a cat with its fur rubbed the wrong way. Dean saw Sam's eyes widen when Cas said the word 'love', but Dean didn't think the angel had noticed. For a celestial being, Cas was very slow on the uptake sometimes.

"It's not only the media that says that," Dean smirked, "I can think of a certain book…"

"Dean, if you're about to give me, an Angel of the Lord, a Bible lesson, Sam's hallucinations will soon become the least of your concerns."

Ah, Cas was definitely cranky. Dean didn't think too closely about why the angel might be so annoyed, that road led to mental images, and that led to wanting to claw his own eyes out. He noticed Sam trying hard not to laugh, and glared at him.

"Violence and threats from an Angel. What's the world coming to?" Dean couldn't help the parting shot, sometimes he wondered if he had a death wish. As Cas's eyes started to smoulder dangerously he decided to convey the information he would have imparted a lot sooner if he hadn't been so disconcerted by…recent events.

"Anyway, while you two were having a nice, relaxing nap, I noticed someone watching the motel room. Either I was followed after I was ambushed, or all Sam's screaming has finally gotten us some unwanted attention."

Cas looked alarmed but Sam only nodded, the brothers had been through this many times before and were experts at disappearing. They both started packing their things with practiced haste while Cas fidgeted by the doorway, clearly unsure what he should be doing. Normally by this point Cas would have taken off to do whatever angel thing he did when he wasn't with the Winchesters; Dean took it as a sign of how much the angel cared about Sam that he stayed.

He was almost finished packing when he heard Sam hiss ' _none of your damn business'_ to the bed, and try to cover it up with a cough. But Dean had become too attuned to the signs of his brother's psychosis to miss something so obvious. He looked up at Cas, who was staring at Sam with a look so intense Dean was mildly astonished that his brother didn't burst into flame. The angel looked over at Dean and they shared a long moment of dismay, the hallucinations had returned far more quickly this time.

His brother and Cas had won this battle, but the war… that was far from over.


	4. Chapter 4

This is a very short section of the story, a moment between Cas and Dean that falls between the chapters, but doesn't really fit into either of them. Cas has a question, Dean tries to answer. Sorry Dean!

 **Chapter 4**

Cas had knocked Sam unconscious before they even got to the car, and now sat in the backseat of the Impala with the hunter's head cradled in his lap. It was only a temporary solution, Sam pulled his way out of unconsciousness too quickly for it to be of any real use, and they couldn't just keep knocking him out every time he saw Lucifer. But Dean hadn't wanted Sam to freak out while he was driving and cause them all to crash.

Dean reached back to grab Sam's wrist and feel his pulse, but Cas bared his teeth and hissed at him. Actually _hissed_ , like a mother cat protecting her kitten.

Dean withdrew his hand slowly and stared at the angel in the rear-view mirror.

"He's my _brother_ , Cas; I'm not going to hurt him."

Cas relaxed with a sigh, seeming embarrassed.

"Sorry, Dean," he mumbled. He sighed again and stared down at Sam. "I don't know what's happening to me."

Dean blew out a breath through his teeth, weighing his options. Silence was good, _great_. But the angel seemed so lost, he decided he had to try and clear a few things up.

"I think," Dean sighed, pausing. He would not have this conversation. He. Would. Not. He looked at the confused face of his best friend. He would.

He started again. "I think that's called, 'being in love', buddy."

Cas absorbed that information.

"But, Dean," he said at last, "it _hurts_."

Dean gave a short bark of laughter. "In that case," he said, "It's _definitely_ love."

Cas met his eyes in the mirror. "You don't approve," he said regretfully.

Dean sighed. How to answer that?

"Of course I approve, Cas. My best friend and my brother? It's the best of both worlds. Plus I was getting sick to the back teeth of Sam mooning around you with those love-sick puppy dog eyes."

"But?" Cas asked, still staring at him.

Dean gritted his teeth. Why was the angel always perceptive at exactly the wrong moments?

"You'll make my brother very happy, Cas, and I'm sure he'll make you happy. I'm happy for both of you. When this is over, we can have family barbecues and drink beer together and watch movies. You two can…" Dean paused. He'd been about to say ' _grow old together_.' In that moment he foresaw a future problem. Assuming any of them survived the next few months, which was looking increasingly unlikely.

He cleared his throat, "buy matching tea towels or whatever it is couples do," he finished lamely.

"But, Sam is only just hanging on to his sanity by the thinnest of thin threads. This…" he made a vague hand gesture, "it's dangerous. If he was to lose you now, it would kill him."

Cas didn't reply, staring out the window instead. Dean could practically hear the angel thinking. He chanced a glance back at his brother, amused to see Cas carding his fingers absently through Sam's hair. He didn't think the angel even realized he was doing it.

"Dean?" Cas asked, a note of hesitation is his voice. He paused and Dean waited for him to gather his thoughts. He gritted his teeth. Please, please _please_ let it not be a question about sex!

"How far are we from Bobby's house?"

Dean was taken aback. "A few hours, why?"

"Can we get a motel near there?" Cas asked. "There's somewhere I want to visit."


	5. Chapter 5

**Warning:** Mentions of Celine Dion. Also, alcohol. Sorry not sorry! More importantly, a bit of hanky panky... if you're not prepared for that, please don't read :)

Thanks so much for reading guys, any comments would be super, super appreciated!

 **Chapter 5**

Dean looked around the motel room with extreme displeasure. He knew they had to stay in motels where people didn't ask many questions; it still amused him that all the shouting, screaming and breaking sounds coming from their last motel room hadn't resulted in any calls to the cops or anyone banging on their door… but _really_?! He looked around again and wondered if they'd accidentally been sent back in time, since it looked like the 70s had come in and thrown up everywhere. The water-stained walls were painted a disgusting bluey-green color, the shag pile carpet had faded from whatever color it had originally been to a suspicious shade of brown, and the beds were like blocks of concrete covered with eye-wateringly patterned bedspreads. There was even a freaking lava lamp on the bedside table.

Actually, the lava lamp was kinda cool.

He sighed, for now it was safe, and that was all that mattered.

Cas had gone off to do whatever mysterious errand had brought them to this neck of the woods, leaving Dean alone with Sam. Although, not entirely alone.

"I didn't mean it like _that_ ," his brother said, sounding scandalized. Dean sighed, Sam's conversation with the invisible Lucifer was beginning to wear them both down.

"Just ignore him!" Dean snapped, regretting his harsh tone almost immediately.

"I can't!" Sam said between gritted teeth. "Whenever I stop answering he starts singing Taylor Swift songs at the top of his lungs. Sometimes…" Sam lowered his voice to a whisper, "sometimes _Celine Dion_ songs."

Dean shuddered.

"No, that was NOT an invitation to sing 'My Heart Will Go On!'" Sam yelled, covering his ears and looking pleadingly at his brother.

Dean considered his options, then got up and went over to his bag.

"There's only one solution, Sam," he said, pulling out a giant bottle of whiskey. "Get so outrageously drunk that any song sounds good."

Sam eyed the bottle warily. "Where did that even come from? We haven't been to a store in ages. Do you just have secret emergency stashes hidden across the country or something?"

Dean looked offended. "Of course I do. Always be prepared, Sam. That's what Dad taught us."

"I think that's actually the Boy Scout motto," Sam looked at the giant bottle again. "Anyway, prepared for what? Prepared for the mother of all hangovers?"

Dean waggled the bottle invitingly.

Sam pondered for a second, perking up as a sudden thought occurred to him. "Hey, do you think Cas can cure hangovers?"

Dean beamed at this unspoken capitulation.

"Only one way to find out!" he grinned. "We'll use ourselves as his test subjects. It'll be a tough job, but sometimes the few have to make sacrifices for the good of the many." The brothers shared a small, slightly bitter smile, acknowledging the truth of that statement.

Dean poured them both an enormous helping of the whiskey, handing one to Sam and holding his own up in a mocking toast. "To science!"

Sam raised his glass and clinked it against Dean's. "To science," he echoed, tossing back the drink in one gulp.

"And to silence," he added, glaring into the air beside the bed.

* * *

Cas looked around the field, noting the similarities and differences between Sam's dreamscape and the real thing. For starters it was noisier in the real world, insects buzzed and hummed, the grass rustled in the wind and the trees at the edge of the field whispered their quiet secrets. It was better in real life, more tactile, more meaningful somehow. Cas felt close to Sam here, could picture the hunter as he had been in the dream, laying back on the grass and staring at the stars.

He'd been wrong about how to help Sam, at least partly; his condition was worsening despite his best efforts. He hadn't fully understood the nature of the hallucinations, what kept them strong, what made them fade. And after Sam's breakdown it was clear it was now too late for the slow approach; Lucifer's influence had grown in Sam like a cancer and nothing was going to stop the final confrontation.

It was just a question of who would win, and how. However, Dean had inadvertently supplied Cas with part of the answer.

Although Sam was happier, so much happier than he had been, his fear of losing Cas had also grown. Fear was what Lucifer fed on; it's what kept him in charge. After their kiss in Sam's first dream, Lucifer's grip had loosened briefly. Sam had been angry, but he hadn't been afraid, had had faith that on some level what Cas was doing was helping him.

It was going to take a combination of things to help Sam now, any of which had a strong possibility of failure. Sam needed to harness his faith in Cas, without fearing losing him. He needed to _know_ that Cas was strong, stronger than his fallen brother. To do that he needed a real memory, something solid and tangible to grasp onto, something with more meaning and power than the visions.

Cas looked around the field again, Sam's safe place, the place he used to go to think about the angel in secret. Yes, this could work.

* * *

When Cas returned to the motel room, he wasn't sure what he expected to find, but it certainly wasn't the Winchesters, Dean lying on the floor, Sam lying on the bed, crying with laughter as Sam screamed out "I'll never let go, Jack!"

As he walked further into the room he tripped over something, or rather several somethings, which clinked together and rolled across the floor. Cas sniffed his disapproval as the bottles came to rest against Dean's foot, making him look up blearily in Cas's direction.

"Hey, Cas!" Dean slurred enthusiastically. "Hey, Sam, your boyfriend's here!"

Sam giggled and hiccuped. "Shhhh!" he said dramatically, flopping his arm off the bed and clamping his hand over Dean's mouth. "S'not my boyfriend!"

Before Cas had time to be more than fleetingly offended Sam rolled onto his back and beamed at the angel.

"Cas's my _angel_ -friend," he corrected, winking drunkenly. Cas felt a mild stab of alarm as Sam tried to roll off the bed and nearly brained himself on some kind of jar filled with…what _was_ that? Some kind of illuminated goo?

Cas was across the room in the blink of an eye. He grabbed Dean off the floor as though lifting nothing heavier than a kitten and deposited him on the other bed, then whirled around and grabbed Sam before he could try, and fail, to get up again.

He pressed his hand down on Sam's shoulder, and the hunter willingly sank back onto the bed, staring up at Cas with naked longing in his eyes. The angel shuddered, almost overwhelmed by an urge to lean down and kiss Sam the way he had in his dreams, but it wasn't the place or the time. Not yet. Especially with Sam too intoxicated to even get off a bed without fatally injuring himself.

The urge to kiss Sam was replaced quickly with the urge to strangle him when the hunter reached out a tentative hand, which was clearly meant for Cas's cheek, but ended up bumping Cas sharply on the nose instead.

"So beautiful, Cas," Sam mumbled. "Dontcha think so Dean?"

Before Dean could answer Cas drew himself up indignantly. "I. Am Not. _Beautiful_!" he ground out. "Flowers are beautiful. Cats are beautiful. I'm an _angel_. I'm…" he floundered, righteous outrage flagging as he failed to find the right words.

"Fetching?" Dean supplied, "Cute? Pretty? _Angelic_?"

Cas glared, until Sam reached out an unsteady hand to place over his heart. "Glorious?" he whispered.

Cas was completely flummoxed. Just as he thought he was starting to understand humans, his friends drank a brewery's worth of alcohol and proved him wrong. What made them think this was a good idea? Where had they even _got_ all that alcohol from?

Sam grabbed Cas's trench coat in his fist and pulled the angel down to sit beside him, then pulled him further down so they were nose-to-nose. Cas put up a token resistance; after all it wouldn't do for anyone to think they could just pull him around like a favorite toy. Not even his Sam. Cas stopped, surprised by the possessiveness of that thought. When had he started thinking of Sam as _his_?

Sam stared into Cas's eyes and the angel felt a flutter of nerves, and something else. The hunter leaned forward fractionally, muttering something that sounded like 'give me cats' but the angel assumed, given the context, was actually 'kiss me, Cas.'

Just before Sam closed the distance between them and kissed the angel for the first time in the world outside of his head, his eyes closed and he fell back against the pillow, unconscious. Dean, who had watched this all unfold, ready to go sleep in the car if things got out of hand, snickered and staggered to the bathroom to throw up.

Cas gently maneuvered the hunter until he looked comfortable on his back, then sighed and stretched out beside him, his hand on Sam's chest in unconscious mimicry of the day he had entered his mind. Sam roused enough to grasp the hand in his own, muttering something that sounded suspiciously like 'love you.' Even with his angel-enhanced hearing Cas couldn't be sure.

 _I love you too, Sam Winchester_ , he thought, allowing himself a small smile as he settled in to watch over his intoxicated human, and wait for the nightmares to begin.

After several hours it became clear Sam wasn't going to have the nightmares, was, in fact, properly asleep without angelic intervention for the first time in over a week. Cas might not have been proficient on human behaviour, but he knew their physiology inside out, knew that alcohol dampened the parts of the human brain that reacted to fear. He also knew that love was remarkably similar to alcohol in that regard.

Cas looked at his unconscious hunter again, and narrowed his eyes. Another piece of the puzzle fell into place.

He had told Dean that love didn't conquer all, but maybe that wasn't entirely true.

* * *

Sam woke up but didn't open his eyes. He could _feel_ the angel staring at him, and knew if he turned his head even a little bit not only would his brains leak out his ears, but he would also bump into Cas's nose.

He gingerly licked his lips, sometime during the night he had clearly been beaten half to death, run over by a semi-trailer, and had some creature die in his mouth.

"Cas?" he croaked, still refusing to open his eyes.

"Yes, Sam?" the angel asked, right next to his ear, as predicted.

"How long have you been watching me sleep?"

"Six hours and twenty-three minutes. Would you like me to heal you?"

"Please," Sam rasped.

Nothing happened. He cracked open an eyelid, tilted his head slightly to the right and looked straight into the smouldering eyes of his angel. He shut his eyes again with a groan.

After another minute of waiting, which was clearly punishment for whatever Sam had done last night, he felt the cool fingertips of the angel and a blessed wave of well-being swept through him, removing all trace of the hangover.

"That's a true, marketable super-power you have there, Cas," Sam sighed in relief. Cas didn't reply and Sam squirmed. He didn't remember Cas turning up last night, so he'd obviously already been pretty much blackout drunk by that point. Drunk and _stupid_ , no doubt.

"Ok, Cas," he said finally. "Let me have it. What did I do?"

"You said he was beautiful," Dean moaned from the other bed. "I'll call you whatever you want Cas, just… fix me too, _please_!"

Cas grumbled something under his breath and Sam felt the bed dip as he moved off to cure Dean of his own self-inflicted pain.

Sam grinned to himself; he'd woken up next to Cas! Sure, he'd been completely wasted when they went to bed and didn't remember a thing, but still. He arranged his expression into something more contrite when the angel glanced back at him, but he kept grinning on the inside. He wanted to wake up next to Cas every day; although next time he could definitely do without the hangover.

The internal grin faded as he watched the angel heal his brother, feeling the too-fast beat of his heart in his chest, and the trembling in his hands that not even a night of sleep and Cas's healing had fixed. Sam wondered grimly how many more mornings, angel-filled or otherwise, he had left.

Once Cas had cured his brother's hangover, he hesitantly asked Dean for money, which was strange enough that Sam would have paid more attention if Lucifer hadn't chosen that exact moment to show up next to him on the bed, where Cas had been moments earlier. Sam tensed, trying to keep his breathing even so as not to alert his brother and the angel, who had started arguing, as usual.

"What's the matter, Sammy?" he asked, with a false moue of disappointment, "Don't you love me anymore? Or am I not exciting enough for you, now you have your new whore to play with?"

"You shut your filthy fucking mouth," Sam hissed. "How dare you? How _dare_ you say that, after what you've done?"

Lucifer shrugged. "I'll say what I like, when I like, Sam. That's how the game is played."

Sam shifted so he was on his side with his back against the wall, as far away from Lucifer as he could get. Lucifer brought up a hand, brushing Sam's hair with his fingertips, a chillingly intimate gesture that caused the hunter to shudder, a horrified whimper clawing its way up his throat.

"Why?" he whispered, as Lucifer trailed his fingers down his cheek.

"Because I can, Sam. When my brother touches you, I want you to think of me, and all the things I will do to hurt you. Not that he'll touch you for long because how could anyone, let alone an _Angel_ , love someone as broken as you?" Lucifer smiled a predatory smile, kissed his fingertips and placed them gently against Sam's lips. He leaned in, and Sam shuddered again as he felt the monster's breath on his cheek. "You have an audience," Lucifer whispered, and vanished. Sam looked up, saw Cas and Dean staring at him with horror, and buried his face in his hands.

* * *

After convincing Dean to give him some money, and knocking Sam unconscious at his insistence, Cas left to go shopping. The countdown timer on the ticking time-bomb that was Sam had clearly sped up; and Cas had no more time to waste. He had to accelerate his own plans.

It took him a while to find a shop that carried what he wanted. Or at least, he thought it had what he wanted. After scouring the aisles for several minutes, he stood in the middle of the shop, feeling completely baffled. What _were_ all these things? What did humans need all this paraphernalia for? Why did they have so many of the same things, with only slight, unnecessary differences between them?

"Can I help you, sir?" a voice asked from behind him. He spun around, startling the shop assistant, a slight, dark-haired woman in her early twenties. May, her name tag read.

"Sorry," he mumbled, embarrassed. "I'm just looking for some things, and I don't know what I'm doing."

"Ah," the girl said, a mischievous twinkle in her eyes. "Shopping for a special someone?"

Cas nodded, surprised. "How did you know?"

May grinned. "The look of total confusion, and the way you poked at the candles like they might come to life and bite you, they were big clues."

Cas smiled uncertainly. The girl ginned even wider. "Why don't you tell me what you want, and I'll see if I can help."

After half an hour of bewildered embarrassment from Cas, and giggles from May, he was finally satisfied that he had what he needed. As he handed over all of the money Dean had given him, unsure if it was not enough or too much, he accidently brushed her hand. He frowned, looking more closely at the girl who had cheerfully helped him, put him at his ease in this strange place. Saw the dark circles under her eyes and the slight tremble in her hands.

"You are… not well," he said uncertainly.

The girl looked at him in surprise. "That obvious is it?" she asked with a sad smile, continuing to ring up the cash register. "I suppose it was bound to show sooner or later."

She sighed, handing Cas his change. "It's a brain tumor," she clarified. At Cas's crestfallen expression she smiled at him. "Don't worry, I've made my peace with it. It's in God's hands now."

Cas looked at the bags he was holding, and back up at the girl, who had put her cheerful mask back in place. He held out his hand, and May took it with a warm smile.

"Be well, May," he said softly, sending a tendril of healing energy into her, enough to root out and destroy the cancer.

"You too. Enjoy your evening with Sam," May said with a wink.

Cas walked out of the shop feeling lighter, and with a renewed sense of purpose. He had made mistakes, so many mistakes. But he still had the ability to do good in this world, and he resolved to bring that ability to bear with full force on the mission in front of him. With that hopeful thought he took his armful of goods and flew away to make some final preparations.

* * *

It was late in the afternoon before Cas had finished struggling and fussing with what, he assumed for most humans, were simple tasks. He had a renewed admiration for the species; these courtship rituals were _not_ easy.

Eventually he was satisfied and flew back to the motel room, where Dean was apparently in the middle of a story, probably intended to distract Sam from Lucifer's presence. Cas flew in, grabbed a surprised Sam, and was gone before Dean even had time to blink.

"Rude," Dean murmured, smiling knowingly to himself as he lay back and switched on the TV.

Sam looked around in surprise. One second he had been sitting in the motel room, half listening to Dean, but mostly freaking out about Lucifer, who'd been running a blade lightly up and down Sam's spine. The next, he was standing in the field. He looked around. Lucifer hadn't come along for the ride apparently; despite residing in his head it seemed to take him a while to make himself known in a new location.

His brain finally caught up with his body and he properly took in the scene in front of him. They were standing in his favorite place, beside a blanket that had a scattering of throw cushions. There was a picnic basket, and close to a hundred candles twinkling like tiny stars. A single red rose lay on top of the basket.

He hissed in a breath, taking a step back and searching for the eyes of his angel, only to find that Cas had gone suddenly shy, looking down at the ground and twisting his fingers nervously.

Sam had thought it wasn't possible to love the angel any more, but the surge of emotion he felt, seeing the effort Cas had gone to; especially since this was _Cas,_ who probably hadn't even known picnic baskets existed, let alone what their use might be, filled him until he thought he'd burst.

"Cas?" he said, gently. Cas still didn't look up. "Cas? Castiel…look at me." He reached out and tilted the angel's head up. Cas met his gaze nervously.

"Is it ok?" he asked, hopefully.

"It's better than ok, Cas," Sam said quietly. "It's perfect. You're perfect."

He moved his hand slowly from Cas's chin, sliding it around the back of the angel's neck, stepping closer, so that only inches separated them. Cas was still looking into his eyes, and Sam thought he could drown in those infinite pools of blue. He felt Cas's breathing speed up, and realized the angel was letting go of the rigid control he normally held over his vessel.

Sam brought his other hand up, to cup Cas's cheek, and the angel hesitantly put his hands on Sam's waist. Ever so slowly, watching Cas's wide eyes until the last possible second, Sam leaned down and kissed the angel.

It was a slow, tender kiss; Sam thought the angel tasted like moonlight with a hint of salt, like the sea at midnight, yet his smell was all ozone and sun-kissed meadows. A combination of light and dark that had Sam's head spinning.

Sam dropped his hand from Cas's neck to the small of his back, pulling the angel gently against him. Cas parted his lips to let out a little sigh of pleasure, and Sam began to kiss him in earnest, with long, lazy sweeps of his tongue, exploring Cas's mouth until the angel melted against him, until Cas raised up a hand and tangled it in Sam's hair. Sam kissed his angel until they were both breathless and the angel was clutching at him like a lifeboat in a storm-tossed sea.

Eventually Sam could take it no more, and started to walk them backwards towards the blanket. Cas broke away suddenly.

"Too many clothes!" he growled, his normally gravelly voice even huskier than usual. Sam heartily agreed. He grinned, reaching out and pushing Cas's coat off his shoulders, undoing his tie and throwing it over his shoulder. They both kicked off their shoes as Sam pushed at the angel gently. Cas got the message and lay down on the cushions. Sam stood over the angel for a moment, an almost predatory glint in his eyes as he shucked his shirt and knelt down, straddling Cas's hips.

"Now," he said, with mock severity, "I don't care if Dean starts screaming that the entire world is on fire, that snakes are falling from the sky, or that aliens have landed and are starting an invasion. We are not leaving here until we finish what we started."

Cas looked into Sam's eyes, nodding. A silent communication passed between them, an acknowledgement that this might be the only time together they would ever have.

Sam reached out a hand, slowly undoing the top button on Cas's shirt. Cas's eyes widened; his lust-glazed expression tightening something in Sam that caused his hand to shake as he undid the second button, ripping it free when it didn't come apart fast enough. Sam leant down and kissed the triangle of skin that had been exposed, licking his way up to Cas's neck, undoing the rest of Cas's buttons with practiced fingers.

As he latched on to Cas's neck, sucking and nibbling with his teeth the angel let out that bone-melting moan Sam remembered from last time. He grinned into Cas's neck, giving it one last lick before moving down Cas's chest, pushing his shirt open. His mouth found a nipple, licking and grazing it with his teeth, and if Sam thought Cas's previous moan had been a turn on it was nothing compared to the noises the angel made now. Sam was so hard he began to wonder if he was going to come without ever removing his pants, like a horny teenager.

Cas was clutching at his shoulders now, squirming beneath him, and Sam finally reached down, smiling mischievously at his angel as he popped the buckle on his belt. Cas growled, and suddenly neither he nor Sam were wearing pants. Sam gasped in surprise, and this time it was the angel's turn to smile with a wicked glint in his eyes.

Sam had a suspicion about what one of the items in the picnic basket might be; kissing his angel to stop the protests that things were moving too slowly, he reached into the basket. Feeling around he found a bottle of lube and grinned against Cas's mouth. He wondered who had helped his angel do his shopping, and thanked them silently. He squeezed some into his hand, and reached between them, taking them both in hand. They both groaned, the sensation was almost too much and Sam knew neither of them were going to last long. The angel was completely lost to lust now, panting and whispering his name, and Sam wasn't in much better shape.

He moved his hand, gripping and releasing in the way he liked, and he could feel Cas going tense under him. He looked down at his angel.

"Look at me, Cas," he said, an echo of his earlier command. Cas looked up him, pupils blown wide, thrusting against his hand and panting. A small whimper emerged from his throat. Sam's breath caught, it was undeniably the hottest thing he'd ever witnessed.

Sam was close now, very close. "That's it, Angel," he whispered, "Let go. Let go, sweetheart. Come for me now. Come for me, Castiel."

At those words, the angel came undone under his touch and Sam himself came so hard he practically blacked out.

When he came to his senses the angel was lying boneless beneath him. Sam shifted to the side so he wouldn't crush Cas, realizing they'd have to move to get cleaned up in a second, but more than content to just lay there for the moment.

"That," Cas said, his voice cracking. "That was…" he paused, seemingly lost for words. Sam smiled.

"Yeah," he said. "It was." He was aware there was a lot more he could have done to the angel, but there was no way either of them had been going to make it that long. He grinned against Cas's shoulder. They had all night, why rush?

Cas shifted, and suddenly both of them were clean. Sam started in surprise, then smiled to himself. Angels were clearly exceptionally handy creatures to have around. He'd better stay in this one's good books.

He wrapped an arm around his angel, and snuggled close. After several minutes where neither of them said anything, content just to feel each other breathe, Sam started to get turned on by the fact that Cas still mostly had his shirt on. That seemed indecently hot, and Sam started to mouth at Cas's arm, dragging the shirt down a bit with his teeth. Cas wriggled, sighing a small sigh that turned Sam on even more. He started pulling at the shirt in earnest, and Cas turned on his side, giving Sam better leverage. Sam paused to reach over and grab the second blanket, pulling it over them as the sun was now low in the sky, dropping the temperature to slightly below comfortable.

Sam rolled Cas so he was on his stomach, and pulled the shirt off, one arm at a time. He ran his fingers over the angel's shoulder blades, exploring with first his fingers, then his mouth. Cas whimpered in pleasure and Sam paused. He wanted to ask a question, but even with the angel naked underneath him, it seemed presumptuous.

"What is it, Sam?" Cas asked, sensing the hesitation.

Sam still didn't say anything, so Cas rolled until he was slightly on his side, looking up at the hunter. He waited patiently, an eyebrow quirked in question.

"I was just wondering…" Sam said, trailing off. "I was just wondering… what your wings looked like." He blushed when Cas seemed genuinely taken aback by the question.

"I didn't mean…I know you probably can't… or don't want to…" Sam ran his fingers through his hair and looked away from the angel, over the fields towards the setting sun.

* * *

Cas was quite sure that no one had ever felt anything like he had felt when Sam had teased his clothes off, and done things to his vessel that had caused Cas to re-evaluate what words like 'pleasure' and 'bliss' and ' _love_ ' meant.

But he was completely unprepared for Sam's question. He looked at the hunter seriously, studying him. He could feel the moment Sam took his silence as a rejection, but he still couldn't put the right words together to explain what that question meant to him.

He used his angelic powers to dress them both from the waist down; he could tell Sam also took that the wrong way, but he felt actually _cold_ , having decided to let his vessel free reign to feel what it wanted to feel tonight, and there was no way he was standing without at least that much protection against the elements.

He stood up and held out his hand to Sam, who took it hesitantly and climbed to his feet. He kept hold of the hand as he looked into Sam's eyes.

"No mortal has ever seen my wings before," he said, holding up a hand when Sam tried to say something. "We don't show them to mortals because they might find the experience… unnerving. Are you prepared for what I will look like? I will no longer pass for human in your eyes."

He was pleased to see Sam taking the question seriously. The hunter nodded.

"I will love you, whatever you look like Cas, and I want to see you. All of you."

Cas nodded, and closed his eyes. He felt for his wings, bringing them into this reality, instead of the dimension outside of human perception where they usually existed.

He heard Sam gasp, but didn't open his eyes, worried about what he'd see in the hunter's face.

But then Sam breathed out an awed whisper, "Oh, Cas… they're _magnificent!,"_ and the angel opened his eyes, to see the hunter staring at him with an expression of wonder and awe and a love so profound it made Cas's heart turn over in his chest. He looked up at his wings, obscurely pleased they had provoked such a reaction in his human. They stretched out well above their heads, the deep midnight black of the feathers shadowing half the field. He stretched them absently, enjoying the feel of the cool air on his feathers.

Sam reached out a hand, meeting Cas's eyes, silently asking permission. He nodded slightly, and when Sam's fingertips traced the line of his wings he shivered violently, surprised by the intensity of the feeling.

Sam drew his hand back in a hurry. "I didn't hurt you, did I?" he asked anxiously.

"No," Cas said, smiling slightly. "It's just strange is all. I can feel you… touching me."

"I've been touching you all evening, Cas," Sam said with a wicked grin. Cas shook his head.

"No, you haven't," he corrected. "You've been touching my vessel. My wings, they are part of _me_. Of my true form."

Sam absorbed this, and Cas could feel the hunter thinking. He started to think too; maybe this would be the tipping point. The time when Sam would finally feel safe in the knowledge that Castiel was more than the vessel that contained him. He knew Sam knew that intellectually, but thought maybe now he would really _feel_ it, in his heart and soul.

Would finally realize that Cas could stand for him against Lucifer and _win_.

* * *

Sam looked at the angel, and felt like he really _saw_ him for the first time. Cas's - _Castiel's,_ he corrected himself, the nickname didn't have the gravity this moment required - wings reached far above and to the sides; outlined against the setting sun, his midnight black feathers looked like they were lined in fire. It made Sam feel humbled to his very core that this magnificent creature loved him, and there could be no doubt that Castiel did love him, despite not having said the actual words. He felt ashamed of all the times he had doubted the angel, or had tried to make him conform to human standards. Because, as Castiel had warned, there could be no mistaking now that he was not even remotely human.

Sam loved him with every atom of his body.

Cas watched his reaction through half-lidded eyes, an almost feline look that had Sam's heart rate speeding up. Deliberately he stepped behind the angel. Cas stood still, his hands at his sides, head turning slightly to watch him. Wrapping an arm around Cas's waist, he lowered his mouth to run his tongue across the spot where his back met his wings, reaching a hand up to carefully, very, very carefully, card a hand through those magnificent feathers. The angel hissed out a breath but stood motionless, although Sam noted the involuntary twitch of a hand and smiled to himself.

"Ok, love?" he asked quietly.

Cas nodded, breathing hard. Sam tightened his hand around his waist, pulling Cas back hard against him, biting down gently as he did so, his hand tightening on Cas's wing.

" _Sam_ ," Castiel hissed, clutching at the hand still holding his waist. Sam continued his gentle assault on Cas's body, paying no heed as the angel got more frantic by the second.

" _Sam!_ " he repeated, more urgently this time. " _Please…_ "

Sam growled, Cas's voice was one of the things Sam had fantasized about the most, and hearing the angel say his name in that husky tone, beg him to ravish his body, it set Sam aflame. He wanted to hear that sexy voice cry out in ecstasy, to see those soul-piercing blue eyes bore into his as he brought them to the brink over and over. Cas went still under his hands, hands which were now digging in to his hip bones with almost bruising intensity. Sam laid his head against the angel's back, breathing heavily, struggling to get himself under control.

Cas's hands came to rest gently over Sam's.

"You're not Lucifer, Sam," he said quietly, in that uncanny way he sometimes had of seeming to read his thoughts. "And I am no fragile human. You can't hurt me." He paused, head tilted to the side, Sam could almost feel him analysing, could imagine the look in his eyes as he mentally put the pieces together, Sam's posture, his breathing, the tremble in his fingers. The angel let out a sigh that sounded almost sad.

"Sam. You're not an abomination; your touch doesn't sully me. You are not unworthy. It is I who am unworthy of you."

Sam exhaled a shuddering breath, letting go of a weight he hadn't even realized he was carrying around. He sank to his knees, turning the angel around. He felt a rush of air, and suddenly they were surrounded by a wall of feathers. He looked up at Cas, who stared back down at him with blue eyes that burned with fiery intensity. Still looking up at the angel Sam leaned forward and mouthed at him through his clothes. Cas's resulting whine was all Sam needed to hear. He quickly undid the angel's pants, Cas was apparently too far gone to help this time, and took him into his mouth, causing the angel to moan again, so loudly this time that Sam was glad the field was far away from any human habitation.

Sam released him. "Lie down," he said roughly, too aroused to be more gentle.

Cas obeyed instantly, lying back against the cushions with more fluidity and grace than a human could ever manage. As Sam waited for him to get comfortable, he quickly got rid of his own pants and knelt down between Cas's legs, pouring more lube into his hand. Cas reached up and grabbed the bottle, flinging it with all his considerable strength across the tops of the trees. Sam stared at him, open-mouthed.

"Too slow," Cas gritted out, by way of explanation.

"But, I don't want to hurt you, Cas," Sam began, trailing off as Cas glared at him.

" _Angel!_ " Cas growled, exasperated, rustling his wings for emphasis.

Sam smirked, leaning down to kiss him.

"You're so fucking hot, you know that right?" he said with a grin, and Cas practically howled at him.

"Stop. _Talking_!"

Sam obeyed, although he took his time, easing into Cas slowly, despite the angel's insistences and squirming. When he was finally fully inside his angel he stared into Castiel's eyes and began to move.

* * *

Castiel stared into the eyes of his hunter, and reached out a hand to gently stroke his face.

"Fuck, Cas," Sam groaned. "Cas… _Castiel_ , I love you, I love you _so fucking much_ I can barely breathe for it!" He leaned down to kiss Cas, whose eyes were shining brighter than the stars. "I love you, Angel," he whispered again, "I love you, _I_ _love you_!"

Cas could feel Sam inside him, his hand around him, and it was an amazing feeling; but it was nothing compared to the feeling those words unfurled in the angel. He reached up, holding Sam's face so he was looking directly into Castiel's eyes.

"I love you, Sam Winchester," he said intently. "I have lived countless centuries, and never have I loved as I love you now. And I never will again. You are the sun and the moon, the mountains and the sea, the stars in the sky. You are my universe, now and forever."

"Cas…" Sam whispered, overcome, and then there was no more room for words, they said all they needed to say with their bodies, staring into each others eyes as the world faded away around them, Cas's wings curling to enfold them in their protection.

As Sam lay beside his angel, staring up at the canopy of stars above them, he felt a small, secret smile tug at his lips. If his past self, who had dreamed of this moment in this very field so many times, could see them now, well…

Sam's quiet laughter roused the angel from his almost catatonic state.

"What's funny?" he asked, sounding more sleepy than curious.

"Oh nothing," Sam said, sitting up and deciding to look in the picnic basket. He looked inside and saw champagne, chocolates, strawberries, and a packet of condoms. He smothered another quick laugh, looking down at the drowsy, adorable angel who was looking up at him with a curious look.

Not that he would ever call Cas adorable to his face. Oh no, he'd learned that lesson.

"Nice job on the shopping," he said instead, reaching out to run his hand through the angel's hair, kissing him softly.

"I'll have to tell May you liked it," Cas said absently, reaching up to touch Sam's face in a soft caress.

"Who's May?" Sam asked curiously, bringing Cas's hand to his lips.

"The girl at the shop," Cas said. "She helped me. She was very nice. She suggested the flameless candles so I wouldn't burn the field down."

Sam grinned against Cas's hand, feeling laughter bubble up inside. He could imagine that conversation. ' _Can I help you sir? Why yes, I wish to copulate with a human male and am unsure about the necessities such a course of action requires.'_

He couldn't hold it in, he snorted with laughter, burying his head in Cas's shoulder, the bemused angel running a hand absently down his back, and that, even more than anything that had come before, felt like love.

* * *

Cas had been disappointed, but not surprised, when Lucifer showed up soon after they returned to the motel room, surprising Dean in the middle of a Dr. Sexy M.D. marathon.

Dean had grumbled something about keeping his brother out past curfew, whatever that meant, and gotten up to make a coffee. He clearly sensed the same thing Cas did, that it would be a long night.

Sam had tensed up, his breathing had quickened and his eyes were wide, but he didn't say anything. He didn't need to. Cas knew the final confrontation was not far away now; the Lucifer hallucination would be getting desperate, feeling Cas's hold over Sam strengthening. He only hoped he'd done enough.

He left Sam trembling in the center of the room, making Dean promise to call him if… _when_ things escalated, before flying off. He knew Lucifer would try to use him against Sam if he stayed, and that couldn't be allowed to happen.

He flew to the park bench he had occupied a few days previously, when he was confused and hurt, with no concept of just how much his feelings for Sam had changed. He was wiser now, and infinitely more resolute. The war between Sam and Lucifer had to play out to its bloody conclusion; when he stepped in either Sam would trust in him and win, or he wouldn't and he would die, taking the angel's heart with him. Castiel closed his eyes and settled in for the agonizing wait.

* * *

Sam stared at Lucifer. He saw the flash of annoyance when Castiel left, and felt relieved that the angel had gone, something he never thought he'd feel.

"That's a shame," Lucifer said regretfully. "I would have liked to carve his pretty eyes out. I think they'd look nice hanging in the Cage, don't you? Festive."

Sam gritted his teeth and didn't reply.

After a few hours of trying to taunt Sam into conversation, Lucifer stepped up his manipulation to new, uncharted heights.

"Oh come on, Sam," he said, throwing his hands up in mock exasperation, "giving me the silent treatment? You know how that ends." Lucifer stepped forward, blade in hand, tracing it slowly down Sam's cheek. When Sam didn't even flinch he vanished the blade and put his hand on Sam's chest, pushing hard, a delighted smile crossing his face when Sam stumbled back a step. Sam sucked in a breath; the implications of that physical interaction weren't lost on either of them.

"Yes, that's right," Lucifer said, with a self-satisfied smirk. "I'm part of you now, Sam, curled through your mind like a snake in the grass. There's no escaping me." He flicked out a hand, raking Sam's neck with his fingernails. Sam put his own hand up, staring with horror at his fingers when they came away wet with blood.

Lucifer licked the blood from his nails contemplatively.

"Your pretty angel can't save you now," he said, smiling darkly. "And when he tries, I'll take control of you; use you to tear him apart. He'll scream your name Sam, but not in ecstasy, in agony, begging you to stop. What I'll make you do to him will make your time with me seem like a sunny Sunday afternoon."

Sam snapped.

* * *

 _'Cas? Cas! Come quick, it's Sam. Hurry_!'

Castiel flew to the brother's side quicker than thought. When he appeared in the motel room he was confronted with Sam, yelling obscenities into thin air.

"Don't you fucking touch him!" he was screaming, brandishing a knife at nothing. Dean was on the other side of the room, clutching a deep gash on his arm. Cas flew to his side, healing the gash, before turning back towards Sam. Dean grabbed his arm and he turned back questioningly.

"I tried to reason with him, but he can't even see me," Dean gasped. "When I grabbed him, he thought I was Lucifer. I thought he'd kill me, but on some level he must have known it was me, because he stopped."

Cas nodded, prying Dean's hand off his arm. Time to end this.

He reached out a hand and grabbed Sam's arm. Sam tried to pull away, but Cas was implacable, the hunter may as well have been trying to pull against a mountain. He pushed into Sam's mind, just a little way, a dangerous proposition while he was still awake, but necessary.

As Cas had thought, by being partly in Sam's mind, he could see Lucifer.

He was standing there, arms crossed, an evil smirk on his face.

"Ah, Castiel. So glad you could finally join the party. I was just telling your little toy what pleasure I'm going to take cutting out your heart and feeding it to him."

Sam growled a feral growl, a sound so inhuman it made the hair on Cas's neck stand on end. He lunged for Lucifer, but Cas's grip was iron, holding Sam back with bruising force.

An angel blade manifested in Lucifer's hand, and he started paring his fingernails with it. Cas tensed, what had to happen next would be unpleasant, but necessary.

Cas had tracked the exchanges between Sam and Lucifer, working out the content from Sam's side of the conversation. He'd noticed a trend, the encounters had gradually gotten more and more physical, as Sam's ability to differentiate between reality and the visions had slowly deteriorated.

It was unlikely that Sam's sanity would break now, not with Cas watching over him, so it had only been a matter of time before the Lucifer hallucination tried to kill him instead. And it would surely kill him, because to Sam, these visions were reality. His mind and body had no more defenses left.

Except one.

If Lucifer was real enough to Sam to pose a threat to his life, then the reverse would also be true.

As Cas had predicted, Lucifer suddenly flipped the blade around, and lunged for Sam. Cas hauled the hunter behind him with all the inhuman strength he possessed, stepping in front of the blade. It plunged straight into his heart.

* * *

What happened next was the most surreal thing Dean had ever experienced, and considering the life he had lived, that was saying something.

One minute Cas had been holding Sam by the arm, staring at a spot on the wall while Sam struggled and cursed. The next he had shoved Sam behind him, practically breaking his brother's arm, and staggered backwards, clutching his chest. Grace started to leak out his fingers, and he made a fist in front of his chest, slowly moving his hand away, as if… Dean's eyes widened… _as if drawing out a blade!_

Sam let out a sound that was so heart-rending Dean felt tears spring to his eyes. His brother sprang toward the angel, but Cas was already moving, darting forward and slamming his fist into the wall. Dean assumed he'd stuck the blade into the hallucination, but to him it just looked like the angel had attacked a random patch of wood paneling.

He stared at Cas, whose grace had begun to shine brightly, so brightly it hurt to look at him. Somewhere a light bulb blew as the shadows of two enormous wings covered the walls. Castiel turned, his eyes blazing with an inhuman intensity, cracks snaking up the walls behind him, tremors running through the floor at his feet.

Dean unconsciously shrank down further behind the bed. This was a side of the angel that he rarely let them see. This wasn't Cas, their friend, who didn't know how to tie his shoelaces without angelic help. This was Castiel the Seraph, in all his glory, and Dean trembled before him.

Sam lunged at the angel, ripping his shirt open and running his hands across Cas's chest, tears streaming down his face.

"Cas, oh god _no_ , Cas, why would you do that?! Cas, oh fuck, _Cas_!" Sam was babbling, completely distraught. Dean imagined the view inside Sam's head was quite different to the view from where he was standing.

Cas grabbed both of Sam's hands and held them tightly to his chest. His grace flared again and Sam's face cleared as he looked down at the smooth, unblemished skin of the angel.

Dean held his breath, feeling like he was watching something incredibly private pass between his brother and the angel. As Sam stood there, shaking, Cas reached out a hand and touched his cheek gently.

"He could not hurt me, Sam. I was stronger than him, because you trusted me to be stronger."

"I thought you died, Cas," Sam whispered, "I thought you died, and it was my fault."

Cas stroked the back of his hand gently down Sam's face, and Sam leaned into the touch.

"No you didn't," he corrected gently. "Deep down, you knew I would always be there for you, will always be there, watching over you." He smiled softly, a love a deep as the ocean in his blue eyes.

"I am here, Sam. I will never leave you, _dilecto meo_."

With those words both his brother and the angel were gone in a flutter of wings. After a few failed attempts to get his feet, Dean finally got his shaky legs underneath him and pulled out his laptop. He smiled softly to himself when he translated the Latin words of the angel.

 _I will never leave you, my beloved_.


End file.
